Dream, I'm unfortunately quite familiar where you are right now, as I've been there for a long time...And at the same time I haven't got a clue where you are, we each occupy our own private hell, and enjoy our own private miseries.
I understand your discontent with your job and it's thanklessness. At work, I often joke that we are the Invisible, in much the same sense of India's Untouchables. We don't really exist until people need us, then we can be seen. Until then we're just faceless drones.
I have no experience with cutting, so I won't comment on it. On the other hand, I used to bite myself. I used to get so mad and frustrated that I couldn't take it. So rather than lashing out, I would simply sink my teeth into my own hand. Trust me when I say it really didn't help much.
IMO, Silly Girl pretty much hit it on the head.
Myself, I try to live day by day. What happened yesterday doesn't matter is it's gone. Tomorrow is of little concern as it's not here yet. Today is the day I have to worry about.
The same applies to the consequences of my actions. I don't expect them to effect the work. Hell I don't expect them to effect things down the street. If I can make one person happy/content then I've done what I can do.
I don't know what else to say, Dream. Take the small victories where you can, and watch for the little prizes life likes to through your way.